摘要:

Studies were carried out in rabbits to localize by electrical stimulation the sites in the hypothalamus that are concerned with the production of hyperglycemia, and to determine the contribution of the sympathetico-adrenal system in producing this effect. Stimulation of the anterior hypothalamic area, paraventricular nuclei, and rostral border of the ventromedial nuclei produced a significant elevation of blood glucose in normal rabbits and also in adrenal-demedullated animals. Corticotropin (ACTH), 2 U/kg, produced a hyperglycemia comparable to that observed following electrical stimulation, whereas growth hormone (GH), 2.5 mg/kg, had no effect on blood glucose. The data indicate that the anterior hypothalamus plays a part in the regulation of blood glucose, which is independent of the sympathico-adrenal system. It is suggested that the hyperglycemia produced by hypothalamic stimulation in these studies is due to the release of one or more anti-insulin factors by the anterior pituitary.

ISSN:0028-3835    

DOI:10.1159/000121897

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Melatonin and testosterone propionate (TP), either alone or in combination, were injected into groups of pregnant rats and into 2-, 6-, and 13-day-old female animals. Melatonin had an inhibitory effect on vaginal introitus and decreased the incidence of estrous smears, when injected during the early postnatal period. TP inhibited the canalization of the vagina in prenatally injected rats and caused precocious vaginal patency in animals injected on days 6 and 13. Female rats given TP alone showed persistent vaginal cornifîcation, while melatonin in combination with TP reduced the incidence of such persistent vaginal estrus and established irregular vaginal cycling

ISSN:0028-3835    

DOI:10.1159/000121898

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Lactating rats were implanted, on the 3rd day post partum, with 27-gauge needles containing melted estrogen, in the mammary gland, pituitary, and the back. A clear inhibition of lactation (measured by daily litter weight gain, milk yield, and microscopical observation of the mammary gland) was observed in mothers with intramammary estrogen implants. In rats bearing estrogen in their backs, the inhibition of lactation observed is attributed to diffusion of the estrogen to the mammary tissue. Direct intrapituitary estrogen did not inhibit lactation, but on the contrary, was followed by a marked stimulation of lactation. It is concluded that the inhibitory effect of estrogen upon lactation in the rat is exerted at the mammary and not at the pituitary level. On the basis of the results obtained, the hypothesis is advanced that the steroid may alter or block the effect of oxytocin or glucocorticoids on mammary function.

ISSN:0028-3835    

DOI:10.1159/000121899

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Electrical activity of the brain during the critical period in the rat was examined throughout the estrous cycle, using chronically implanted macro-micro electrodes. Slight circadian rhythms were observed in the basal level of the integrated multiple unit activity (MUA) in the basal hypothalamus and forebrain limbic area. In addition to these changes, a gradual increase of MUA in the basal hypothalamus was observed during the evening of diestrus day 2, while there was no change in the forebrain limbic preoptic area. However, a characteristic elevated pattern of MUA appeared for 12 to 25 min during the critical period (2 p.m. to 4 p.m.), both in the basal hypothalamus and forebrain limbic preoptic area, i.e., in the arcuate nucleus (ARC), ventromedial hypothalamic nucleus (VMH), medial preoptic area (MPO), septum (SEPT), amygdala (AMYG) and bed nucleus of stria terminalis (BST). The episodes of the characteristic pattern were also observed in the basal hypothalamus on the afternoons of diestrus day 2 and estrus, as well as in the forebrain limbic preoptic area on the day of estrus. To determine the possible relationship between the characteristic pattern and gonadotrophin release, electrochemical stimulation was applied to the areas of the brain where the characteristic pattern was observed during the critical period. Ovulation could be induced by stimulation of the ARC, MPO, SEPT, AMYG, and BST, but not by stimulation of the reticular formation (RF) and hippocampus (HPC). Furthermore, the results shed light on the facilitatory and inhibitory effects of progesterone on ovulation and the onset of the critical period.

ISSN:0028-3835    

DOI:10.1159/000121900

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The effect of α-methyl tyrosine or p-chlorophenylalanine pre-treatment of rats was tested on the ability to respond to anacute stress, a chronic stress, and to reserpine-induced ACTH hypersecretion. This pretreatment had no effect on any of these pituitary responses or on the depletion of CRF that accompanies the administration of reserpine

ISSN:0028-3835    

DOI:10.1159/000121901

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Antidiuretic (AD) activity was studied in the following regions of the dog brain: hypophysis (1); supraoptic and preoptic areas (2); medio-ventral hypothalamus (3); medio-dorsal hypothalamus and anterior thalamus (4); posterior thalamus (5); mammillary area (6); mesencephalon (7); temporal cortex (8); and caudate nuclei (9). AD activity was found in the samples derived from the hypophysis, hypothalamus, thalamus, and mesencephalon (brain region 1 to 7), while samples of the temporal cortex (8) and the caudate nuclei (9) showed no activity. The AD activity present in the hypophysis (1) and in ventral hypothalamic regions (2, 3 and 6) was due to the substance(s) whose activity was dependent upon an intact disulphide bond, mainly vasopressin. The AD activity in the thalamus (5) and in the mesencephalon (7) was only partially dependent on the vasopressin content.

ISSN:0028-3835    

DOI:10.1159/000121902

出版商:S. Karger AG    

年代:1970

数据来源: Karger